Speaker
Description
We study the possibility of resonant production of millicharged scalar particles by a timelike ($k^2>0$) electromagnetic wave, which can be experimentally obtained in plasma or in a medium with refractive index $n < 1$ (metamaterial). We show that the classical Klein-Gordon equation for the millicharged scalar field reduces to the Mathieu equation, which has exponentially growing solutions in certain areas of a parametric plane. We determine the area in momentum space of outgoing particles, for which the resonance occurs, and calculate the Floquet exponent which determines the rate of the resonance. Considering the cases of intense running and standing radio waves in a metamaterial with $n < 1$, we determine the projective bounds on the charge and mass of a millicharged scalar which can be obtained experimentally.
